| Flexible electronics and flexible sensors are becoming the focus of research community.The realization of low-cost,high precision printing and patterning is crucial to the current manufacturing of flexible printed electronics.Traditionally,the printed flexible electronics adopts a Roll-to-Roll process,which can be printed on a large area of the base material,and offer the virtues like high speed and high output.But the critical dimension or the feature size is normally larger than 50 ?m.Therefore,in order to meet the requirements like high-precision,Roll-to-Roll,low-cost,the imprinting technique has become one of the most promising solutions.By using the elastic stamp,the imprinting process can quickly pattern the polymer and the conductive metal while being compatible with common flexible substrates.Inspired by the high-viscous mucus secreted by mussels,poly-dopamine(PDA),a biomimetic polymer film,is attracting more and more attention.Polydopamine can be obtained by simple polymerization of dopamine in a weakly alkaline solution,and has advantages such as high adhesion and simple preparation.It has been demonstrated that polydopamine layers on the order of tens of nanometers thickness can be formed on almost all material surfaces and acts as the adhesion layer.Polydopamine has been studied for applications in biology,chemistry,energy,and materials science intensively.In addition,the functional groups such as phenolic hydroxyl groups,possessed by polydopamine itself,have the capability to reduce catalytic metal ions.By electroless plating,metal patterning on the flexible substrate can be realized easily.In this thesis,the patterning of metal on flexible substrates was realized by embossing method and polydopamine,and the preparation process of gas sensor and wireless ion sensor based on imprinting was further developed.It is mainly divided into the following sections:1.Patterning and metallization on a flexible polyimide(PI)substrate based on an embossing process was studied.First,the patterned PMMA mask is formed on a flexible polyimide substrate by elastic stamping.Secondly,silver metal films and nickel metal films were patterned on polyimide using combination of surface modification and ion exchange(SMIE)technology.In open air,the fine interdigitated electrodes(IDEs)structure with metal line width of 10?m was fabricated on a flexible polyimide substrate.At last,the gas sensors based on Cu-Sn oxide was established by electroplating Cu-Sn onto the IDEs and following the thermal oxidation.The testing results indicated that the sensors has a good response to hydrogen gas.The process established offer the properties like high operability,low environmental requirements,and good graphic quality.2.In term of the unique biomimetic adhesion and the film-forming properties of polydopamine,the micro-contact imprinting and the metal patterning method on flexible substrates were studied.By using a patterned elastic stamp,micro-contact printing of polydopamine motifs can be achieved by simply soaking the dopamine solution.With chemical electroless plating,metal deposition of polydopamine patterned portions can be achieved.The conductive properties and fatigue resistance of graphitized metals based on polydopamine were studied and tested.And the spiral inductor devices were fabricated for use in wireless RFID sensors.3.The application of electrodes based on polydopamine to ion selective sensors was studied.Through the method of layer-by-layer imprinting,the preparation of ionselective sensors was realized and applied in practical detection.The related preparation process and electrochemical sensing principle were studied,and the ion selective sensor was used to detect the solution pH and metal ions.By combining wireless RFID sensor systems,a wireless intelligent ion selective sensor flexible tag is manufactured,and the sensor can be applied to wearable devices and food real-time detection. |
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